Chapter 9: Concrete Form Construction

Matching

Match terms to their definitions. Write the corresponding letters on the blanks. Not all terms will be used.

True/False

Write True or False before the statement.

1. Footings are the first part of a building to be installed.

2. Building forms for slabs, walks, and driveways are exactly the same as building continuous footing forms.

3. A vapor retarder provides a barrier to soil gases, such as radon.

4. All wall form systems use similar components to make them perform as expected.

5. Outside corners of concrete-forming systems are created by attaching panels to angle irons with wedges.

6. Walers are difficult to install on forming systems.

7. Riser form boards for stairs are beveled on the top edge.

8. Water should be added to concrete so that it flows into forms without working it.

9. A slump test shows the wetness or dryness of a concrete mix.

10. Curing agents placed on green concrete contain harmful chemicals.

Multiple Choice

Choose the best answer. Write the corresponding letter on the blank.

1. A combined slab foundation/footing is called a slab.

1. dual-duty
2. monumental
3. colossal
4. monolithic

2. When applying a vapor barrier of heavy plastic film under concrete, it should be lapped and sealed.

1. no more than 2 inches
2. between 1 and 3 inches
3. approximately 3 inches
4. at least 4 inches

3. is the only insulation recommended for ground contact and can be placed between concrete and the subsoil.

1. Extruded polystyrene
2. Extruded aluminum
3. Polyethylene
4. Polypropylene

4. The snap ties run through form boards and are wedged against additional form supports called .

1. form panels
2. anglers
3. walers
4. studs

5. Concrete-forming system panels are tied together with wedges.

1. formed plastic
2. wood or steel
3. concrete
4. polyethylene

6. The width of a step is called the .

1. rise
2. run
3. tread
4. edge

7. Which of the following statements about the placement of concrete is true?

1. Working it by hand will cause voids or honeycombs.
2. Vibrators should not be used with a stiff mixture.
3. Overvibrating decreases the lateral pressure on a form.
4. Vibration allows trapped air to escape the concrete.

8. Concrete must be protected from freezing for after being placed.

1. at least four days
2. a minimum of ten days
3. no less than two weeks if the air is humid
4. between ten days and two weeks depending on humidity

9. If moist-cured for seven days, concrete strength will be full strength.

1. up to about 60 percent of
2. more than 75 percent of
3. kept to less than 40 percent of
4. nearly or completely at

Terms

Read the descriptions of terms associated with concrete construction. Write the correct term on the corresponding blanks.

1. Provide a base on which to spread the load of a structure over a wider area of the soil

2. Provides a lock between the footing and the foundation wall

3. Hold wall forms together at the desired distance apart; support both sides against lateral pressure of concrete

4. Used to reinforce concrete floor slabs resting on the ground, driveways, and walks

5. Performed by inspectors on a job to determine the consistency of the concrete

Put in Order

Put in order the following steps for constructing footing forms. Write the corresponding numbers on the blanks.

A. Fasten the spreaders across the form at intervals necessary to hold the form the correct distance apart.

B. Stretch lines back on the batter boards in line with the outside edge of the footing.

C. Erect the inside forms in a manner similar to the outside forms.

D. Drive corner stakes to the correct elevation and stretch lines between the stakes, if desired.

Identify

Identify the following items use with concrete construction. Write the correct name on the line next to the item.

1.

Courtesy of Dayton/Richmond Concrete Accessories.

2.

Courtesy of Dayton/Richmond Concrete Accessories.

3.

© 2016 Cengage Learning^®

4.

© 2016 Cengage Learning^®

Procedures

Read the following procedures. Determine what procedure is being described and write the name of the procedure on the blank.

Procedure 1:

• Stretch lines again on the batter boards aligned with the outside of the foundation wall.
• Set panels directly on the concrete footing to the chalk line or on 2 × 4 or 2 × 6 lumber plates.
• Erect the outside wall forms first.
• Erect the panels for the inside of the wall.
• Install the walers. Let the snap ties come through them and wedge into place.
• Reinforce the corners with vertical 2 × 4s.
• If necessary, form the wall at intervals for the construction of pilasters, thickened portions of the wall.
• Brace the walls inside and outside as necessary to straighten them.
• The top surface of the concrete must be level and smooth to make attaching the wood frame easier.
• Set the anchor bolts into the fresh concrete.
• Install blockouts for larger openings.
• Install forms for girder pocket blockouts.

Procedure 2:

• Determine the rise and run of each step and lay them out on the inside of the existing walls or form.
• Secure cleats (short strips of wood) to the side wall form at each riser location.
• For earth-supported stairs, place fill that is free of organic matter and compacted in place to reduce settling.
• For suspended stairs, construct a support made of plywood, joists, shores, and stair horses.
• Install the rebars or reinforcing as specified by the prints.
• Install riser boards that are ripped to width to correspond to the height of each riser.
• Brace the risers from top to bottom at mid-span.

Calculations

Use the information provided to complete your calculations. Write answers on the lines provided within the exercises.

Estimating the Amount of Concrete for a Slab

Estimate the cubic yards of concrete for the slab shown below. The depth of the slab is 6 inches. Use the space provided for your calculations.

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Total cubic yards:

Estimating the Amount of Concrete for a Footer

Estimate the cubic yards of concrete for a footer. Use the space provided for your calculations.

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Total cubic yards:

Estimating Concrete Materials

Estimate the materials for a complete poured concrete foundation for a rectangular building 32' × 60'. Poured walls are 8 feet tall and 8 inches thick. Form boards are 12 feet long, and rebar is 20 feet long.

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A direct shear test is conducted on a large specimen of dry sand (square cross section with following dimensions: 7.5 cm x 7.5 cm x 3.0 cm [height], Mass = 271.0 g) with a normal stress of 500 kPa. Failure occurred when the horizontal force was 1.96 kN. For the same sand, tests were also conducted to determine the specific gravity and the maximum and minimum void ratios. These tests yielded the following results: Gs= 2.65, emax=0.80, emin = 0.45. a) Calculate the relative density of the sand specimen b) Determine the friction angle of the soil. c) A triaxial specimen (H= 8.0 cm, D = 3.8 cm, Dr~45%) is prepared using the same sand. The test is performed on a saturated specimen with a chamber pressure of 500 kPa and an initial value of the pore pressure u of 100 kPa. Assuming that the results of the direct shear test can be used to predict those of the triaxial test, at what value of the total axial stress does the triaxial specimen fail?

2. The La Salle Bus Company has decided to purchase a new bus for $95,000 with a trade-in of their old bus. The old bus has a BV of $10,000 at the time of the trade-in. The new bus will be kept for 10 years before being sold. Its estimated SV at that time is expected to be $15,000.

a. Determine which asset class of the bus.
b. Determine annual Straight-Line Depreciation charge.

Shouldgovernment (state or federal) subsidies be provided to rural communities for the recycling of paper, plastics, glass, and tin cans? What are the advantages and disadvantages of such subsidies? Could the money that would be spent on such subsidies be spent more effectively? How?

Consider a lake with 65 × 106 m2 of surface area for which the only source of phosphorous is the effluent from a wastewater treatment plant. The lake is receiving a flow rate of 1 m3/s from the wastewater treatment plant, which has a phosphorous concentration of 20 mg/L. The lake is also fed by a stream having 20 m3/s of flow with no phosphorous in it. If the phosphorous settling rate is estimated to be 10 m/yr. (a) Write down the phosphorous mass balance equation for the lake and draw a control volume diagram for the lake showing influent streams, effluent streams, point-discharge source. (b) Estimate the average phosphorous concentration in the lake at steady-state. (c) Bonus Q: What level of phosphorous removal at the treatment plant would be required to keep the average lake concentration below 0.02 mg/L?

For construction project risk and conflict management: Provide a comparison between Dispute Resolution Techniques and compare them based on their process time, cost, and legal aspects.

The room is 5*6
Steel yield stress (fy = 60000 psi)
Concrete ultimate compressive strength (f’c = 4000 psi)
Reinforced concrete density = 150 lb/ft3.
Normal weight concrete is used.

The slab is treated as a one way slab and subjected to a dead load of 120 psf (excluding the self-weight
of the slab) and a live load of 220 psf.
- The slab is supported by beams on the edges.
- There is a column at each corner of the slab supporting the beams.
- Each beam is sitting on a non-load-bearing wall.
Design
- The slab
- The beams
- The columns
Carry out all ACI code checks and sketch your designs.

Q2. a) Explain the penetration test carried out on bitumen, state its significance and draw the test apparatus.

b). Mention the main factors considered in the choice of construction materials at the design office – is any of them more important than the other?

c). What factors affect the weldability of steel?

d). Consider the iron value chain from material extraction to disposal, at what point according to your assessment is the most energy used? As a design engineer, at what stage do you think is your intervention most important and what role can you play in making iron more sustainable?

why we don't use density，average speed，and volume to describe the intersection LOS(LEVEL OF SERVICE)

Compare the methods of measuring tensile strength by (a) direct tension; (b) splitting tension; (c) flexure.

What is truly elastic material? Is concrete truly elastic? If not, why? Describe the various stages of micro cracking when a concrete specimen is loaded to failure (please use sketches to explain the behavior and the micro cracking).

1. What is the best system to use for thermal control?
2. When would perimeter radiant heating be most logical as the primary means of thermal control?
3. What are some of the benefits of a central environmental control system over distributed "individual" systems?
4. What are some of the benefits of using distributed "individual" systems over a central environmental control system?
5. Sustainability ("Development that meets the needs of the present without compromising the ability of future generations to meet their own needs") is often assumed to be concerned with reducing energy use, minimizing environmental pollution, maximizing our natural resources, and even providing economic savings. How might these related concerns actually be in conflict with each other?

The detail of column and pad footing are as under:                                                                             [5]

                Size of column: 300 mm x 300 mm.                                                                                           

Live load on column: 900 kN.

Dead load on column: 1200 kN.

Soil Bearing Pressure: 180 kN/m² and Depth of footing as 400 mm

Nominal cover: 50 mm and 20 mm diameter bars for reinforcement

1. Design the footing for bending.     
2. Check the footing in two way shear.         

iii. Write the reasons for considering the service loads for dimensioning of the footing and factored loads for calculating the factored soil pressure.

2. Consider f_cu=40 N/mm², f_y=460 N/mm², severe exposure condition and 2 hours of fire resistance for all the questions.
3. Use B.S 8110 for all your calculations and references.
4. Draw the structural detailing after designing each member for all the questions.
5. Unit weight of concrete as 25 kN/m³